Field
The following description relates generally to wireless communications, and more particularly to identifying resources upon which an acknowledgment (ACK) can be sent or received based upon a criterion recognizable by an anchor cell base station and a non-anchor cell base station in a wireless communication environment that employs coordinated multi-point (CoMP).
Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), and/or multi-carrier wireless specifications such as evolution data optimized (EV-DO), one or more revisions thereof, etc.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
Traditionally, in a wireless communication network with multiple base stations and multiple mobile devices, each mobile device is typically associated with a particular one of the multiple base stations. For instance, a mobile device can be associated with a given base station as a function of various factors such as signal strength, Channel Quality Indicator (CQI), and so forth. Thus, the mobile device can be served by the given base station (e.g., uplink and downlink transmissions can be exchanged there between, . . . ), while other base stations in vicinity can generate interference.
Moreover, cooperation between base stations has become more commonly leveraged. In particular, multiple base stations in a wireless communication network can be interconnected, which can allow for sharing data between base stations, communicating there between, and so forth. For instance, in a wireless communication network deployment across a city, base stations included in the deployment can serve a set of mobile devices located within proximity of the base stations. Thus, multiple sources and/or destinations can be utilized as part of a cooperation strategy for transmission and reception of data, control signaling, and/or other information between devices in the wireless communication network. Use of multiple sources and/or destinations for respective transmissions can yield higher data rates, improved signal quality, and other such benefits. According to an example, the wireless communication network can be a network multiple-input multiple-output (N-MIMO) system or a coordinated multi-point (CoMP) system, in which a plurality of base stations can cooperate to exchange information with one or more mobile devices.
Conventionally, when multiple base stations cooperate as part of an N-MIMO system or CoMP system, non-anchor cell base stations that lack responsibility for scheduling a mobile device or exchanging control signaling with the mobile device can be unable to recognize resources that can be utilized by the mobile device for sending an acknowledgment (ACK) over an uplink. Thus, non-anchor cell base stations can typically fail to demodulate, detect, receive, etc. an acknowledgment over-the-air sent by the mobile device via the uplink. Rather, non-anchor cell base stations oftentimes obtain information concerning the acknowledgment transmitted over the uplink by the mobile device from an anchor cell base station that receives the acknowledgment over-the-air and forwards such information via a backhaul. By way of another example, non-anchor cell base stations in conventional N-MIMO or CoMP systems can commonly be unable to identify resources to employ for sending an acknowledgment over a downlink to a mobile device.